#include "playlistlistmodel.h"

#include <QMimeData>

#include "core/logging.h"

PlaylistListModel::PlaylistListModel(QObject* parent)
    : QStandardItemModel(parent), dropping_rows_(false) {
  connect(this, SIGNAL(dataChanged(QModelIndex, QModelIndex)),
          SLOT(RowsChanged(QModelIndex, QModelIndex)));
  connect(this, SIGNAL(rowsAboutToBeRemoved(QModelIndex, int, int)),
          SLOT(RowsAboutToBeRemoved(QModelIndex, int, int)));
  connect(this, SIGNAL(rowsInserted(QModelIndex, int, int)),
          SLOT(RowsInserted(QModelIndex, int, int)));
}

void PlaylistListModel::SetIcons(const QIcon& playlist_icon,
                                 const QIcon& folder_icon) {
  playlist_icon_ = playlist_icon;
  folder_icon_ = folder_icon;
}

bool PlaylistListModel::dropMimeData(const QMimeData* data,
                                     Qt::DropAction action, int row, int column,
                                     const QModelIndex& parent) {
  dropping_rows_ = true;
  bool ret =
      QStandardItemModel::dropMimeData(data, action, row, column, parent);
  dropping_rows_ = false;

  return ret;
}

QString PlaylistListModel::ItemPath(const QStandardItem* item) const {
  QStringList components;

  const QStandardItem* current = item;
  while (current) {
    if (current->data(Role_Type).toInt() == Type_Folder) {
      components.insert(0, current->data(Qt::DisplayRole).toString());
    }
    current = current->parent();
  }

  return components.join("/");
}

void PlaylistListModel::RowsChanged(const QModelIndex& begin,
                                    const QModelIndex& end) {
  AddRowMappings(begin, end);
}

void PlaylistListModel::RowsInserted(const QModelIndex& parent, int start,
                                     int end) {
  // RowsChanged will take care of these when dropping.
  if (!dropping_rows_) {
    AddRowMappings(index(start, 0, parent), index(end, 0, parent));
  }
}

void PlaylistListModel::AddRowMappings(const QModelIndex& begin,
                                       const QModelIndex& end) {
  const QString parent_path = ItemPath(itemFromIndex(begin));

  for (int i = begin.row(); i <= end.row(); ++i) {
    const QModelIndex index = begin.sibling(i, 0);
    QStandardItem* item = itemFromIndex(index);
    AddRowItem(item, parent_path);
  }
}

void PlaylistListModel::AddRowItem(QStandardItem* item,
                                   const QString& parent_path) {
  switch (item->data(Role_Type).toInt()) {
    case Type_Track: {
      // const int id = item->data(Role_TrackId).toInt();
      // TODO
      break;
    }

    case Type_Playlist: {
      const int id = item->data(Role_PlaylistId).toInt();
      playlists_by_id_[id] = item;
      if (dropping_rows_) {
        emit PlaylistPathChanged(id, parent_path);
      }

      break;
    }

    case Type_Folder:
      for (int j = 0; j < item->rowCount(); ++j) {
        QStandardItem* child_item = item->child(j);
        AddRowItem(child_item, parent_path);
      }
      break;
  }
}

void PlaylistListModel::RowsAboutToBeRemoved(const QModelIndex& parent,
                                             int start, int end) {
  for (int i = start; i <= end; ++i) {
    const QModelIndex idx = index(i, 0, parent);
    const QStandardItem* item = itemFromIndex(idx);

    switch (idx.data(Role_Type).toInt()) {
      case Type_Playlist: {
        const int id = idx.data(Role_PlaylistId).toInt();
        QMap<int, QStandardItem*>::Iterator it = playlists_by_id_.find(id);
        if (it != playlists_by_id_.end() && it.value() == item) {
          playlists_by_id_.erase(it);
        }
        break;
      }

      case Type_Folder:
        break;
    }
  }
}

QStandardItem* PlaylistListModel::PlaylistById(int id) const {
  return playlists_by_id_[id];
}

QStandardItem* PlaylistListModel::FolderByPath(const QString& path) {
  if (path.isEmpty()) {
    return invisibleRootItem();
  }

  // Walk down from the root until we find the target folder.  This is pretty
  // inefficient but maintaining a path -> item map is difficult.
  QStandardItem* parent = invisibleRootItem();

  const QStringList parts = path.split('/', QString::SkipEmptyParts);
  for (const QString& part : parts) {
    QStandardItem* matching_child = nullptr;

    const int child_count = parent->rowCount();
    for (int i = 0; i < child_count; ++i) {
      if (parent->child(i)->data(Qt::DisplayRole).toString() == part) {
        matching_child = parent->child(i);
        break;
      }
    }

    // Does this folder exist already?
    if (matching_child) {
      parent = matching_child;
    } else {
      QStandardItem* child = NewFolder(part);
      parent->appendRow(child);
      parent = child;
    }
  }

  return parent;
}

QStandardItem* PlaylistListModel::NewFolder(const QString& name) const {
  QStandardItem* ret = new QStandardItem;
  ret->setText(name);
  ret->setData(PlaylistListModel::Type_Folder, PlaylistListModel::Role_Type);
  ret->setIcon(folder_icon_);
  ret->setFlags(Qt::ItemIsDragEnabled | Qt::ItemIsDropEnabled |
                Qt::ItemIsEnabled | Qt::ItemIsSelectable | Qt::ItemIsEditable);
  return ret;
}

QStandardItem* PlaylistListModel::NewPlaylist(const QString& name,
                                              int id) const {
  QStandardItem* ret = new QStandardItem;
  ret->setText(name);
  ret->setData(PlaylistListModel::Type_Playlist, PlaylistListModel::Role_Type);
  ret->setData(id, PlaylistListModel::Role_PlaylistId);
  ret->setIcon(playlist_icon_);
  ret->setFlags(Qt::ItemIsDragEnabled | Qt::ItemIsEnabled |
                Qt::ItemIsSelectable | Qt::ItemIsEditable);
  return ret;
}

QStandardItem* PlaylistListModel::NewTrack(const Song& song) const {
  QStandardItem* ret = new QStandardItem;
  ret->setText(song.artist() + " - " + song.title());
  ret->setData(PlaylistListModel::Type_Track, PlaylistListModel::Role_Type);
  ret->setData(song.id(), PlaylistListModel::Role_TrackId);
  ret->setIcon(track_icon_);
  ret->setFlags(Qt::ItemIsDragEnabled | Qt::ItemIsEnabled |
                Qt::ItemIsSelectable);
  return ret;
}

bool PlaylistListModel::setData(const QModelIndex& index, const QVariant& value,
                                int role) {
  if (!QStandardItemModel::setData(index, value, role)) {
    return false;
  }

  switch (index.data(Role_Type).toInt()) {
    case Type_Playlist:
      emit PlaylistRenamed(index.data(Role_PlaylistId).toInt(),
                           value.toString());
      break;

    case Type_Folder:
      // Walk all the children and modify their paths.
      UpdatePathsRecursive(index);
      break;
  }

  return true;
}

void PlaylistListModel::UpdatePathsRecursive(const QModelIndex& parent) {
  switch (parent.data(Role_Type).toInt()) {
    case Type_Playlist:
      emit PlaylistPathChanged(parent.data(Role_PlaylistId).toInt(),
                               ItemPath(itemFromIndex(parent)));
      break;

    case Type_Folder:
      for (int i = 0; i < rowCount(parent); ++i) {
        UpdatePathsRecursive(index(i, 0, parent));
      }
      break;
  }
}